I think you did a great job considering the lighting on the face. That is a difficult face to draw, value wise, because you get the light from the back. So everything apart from the light on the forehead left and the cheek left is in the shade. The way you drew the face is great, truly. If you would like to get more expressiveness in your drawing. Try to shade almost the entire face (leave the lights on the forehead and cheek out) and then use the next darker value to shade in the eye sockets and everything under the cheeks. Maybe not the teeth. And then use the core shadow for the eyes, the lower lip and the folds in the skin. So use only four values. Hope this helps.

It looks overall good! Nice wirk!👍eye brow to me are bit narrow, they seem more dominant on the original photo. Your dark line coming from his eye socket feels quite sharp where the plane changes, while person looks to me more round and soft...